> From: Michal Hocko <mhocko@xxxxxxxxxx> > Sent: Tuesday, January 14, 2020 5:51 PM > To: Tianyu Lan <Tianyu.Lan@xxxxxxxxxxxxx> > Cc: David Hildenbrand <david@xxxxxxxxxx>; lantianyu1986@xxxxxxxxx; KY > Srinivasan <kys@xxxxxxxxxxxxx>; Haiyang Zhang <haiyangz@xxxxxxxxxxxxx>; > Stephen Hemminger <sthemmin@xxxxxxxxxxxxx>; sashal@xxxxxxxxxx; > akpm@xxxxxxxxxxxxxxxxxxxx; Michael Kelley <mikelley@xxxxxxxxxxxxx>; linux- > hyperv@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; linux-mm@xxxxxxxxx; > vkuznets <vkuznets@xxxxxxxxxx>; eric.devolder@xxxxxxxxxx; vbabka@xxxxxxx; > osalvador@xxxxxxx; Pasha Tatashin <Pavel.Tatashin@xxxxxxxxxxxxx>; > rppt@xxxxxxxxxxxxx > Subject: Re: [EXTERNAL] Re: [RFC PATCH V2 2/10] mm: expose > is_mem_section_removable() symbol > > On Mon 13-01-20 14:49:38, Tianyu Lan wrote: > > Hi David & Michal: > > Thanks for your review. Some memory blocks are not suitable for hot- > plug. > > If not check memory block's removable, offline_pages() will report > > some failure error e.g, "failed due to memory holes" and "failure to > > isolate range". I think the check maybe added into > > offline_and_remove_memory()? This may help to not create/expose a new > interface to do such check in module. > > Why is a log message a problem in the first place. The operation has failed > afterall. Does the driver try to offline an arbitrary memory? Yes. > Could you describe your usecase in more details please? Hyper-V sends hot-remove request message which just contains requested page number but not provide detail range. So Hyper-V driver needs to search suitable memory block in system memory to return back to host if there is no memory hot-add before. So I used the is_mem_section_removable() do such check.
